Silicone Sheet in Continuous Rolls

Stockwell Elastomerics maintains a full inventory of solid silicones that have been calendered and rotocured in 36″ wide continuous rolls, in thicknesses from .015″ to .125″ thick. Silicone sheet that has been calendered and cured in an autoclave or rotocured will usually have tighter thickness tolerances than molded sheets.

Most manufactured silicone rubber sheet is cured from gum based silicone – specifically methyl vinyl silicones, which meet a number of military, AMS and industrial specifications. These common silicones have a durometer range of 25 to 70 shore A, and the temperature range for these silicones is generally -100ºF to 500ºF.

The methyl-based gum silicones can be compounded to have high elongation, flex, tensile and tear properties for mechanically demanding properties. Stockwell Elastomerics inventories high strength silicone sheet in thicknesses and durometers ranging from .015″ to .125″ thick and in 30, 50 and 70 Shore A.

Relatively new liquid silicone rubber sheet (LSR) is cast and cured into thin gauge continuous rolls from .010″ to .032″ thick in 36″ widths. The most commonly available LSR sheet materials are provided in 10 to 40 durometer Shore A. LSR compounds have a platinum cure system, which decreases out-gassing and makes these silicone products more friendly to electronic, medical and optical applications.

Specialty Silicones in 12″ x 12″ Molded Sheets

Stockwell Elastomerics has in-house compression molding capabilities, which allows us to provide 12″ x 12″ molded gum based silicone sheets in virtually any thickness from .020″ through .500″ thick. Fast-turn and short run molding of custom silicone sheets in many non-standard compounds, durometers and specifications are available for prototyping and initial production requirements. Examples of special compounds include phenyl based silicones for extreme low temperature (-130ºF), flame retardant, semi-conductive and electrically conductive silicones, thermally conductive silicones and others.

Stockwell Elastomerics has also developed a 12″ x 12″ injection molding process to support the needs of customers requiring liquid silicone rubber (LSR) in sheets, .032″, .062″, .125″ and .188″ thick. The present durometer range is 5 to 70 durometer shore A. Special colors and pressure sensitive adhesive backings are often provided on sheets molded with this unique capability – these are often water jet cut into made-to-order gaskets from customers’ electronic dxf files.

Specifications Met by Silicone Rubber

The most frequent specifications requested are ZZ-R-765, ZZ-R-765b or ZZ-R-765e. The ZZ-R-765 military specification is now listed within A-A-59588. The same convention applies; ZZ-R-765 Class 1 calls out extreme low temperature phenyl base silicone, ZZ-R-765 Class 2 calls out general purpose, low compression set methyl-vinyl silicone and ZZ-R-765 Class 3 calls out high tear strength grades of silicone.

Silicone Sheet in 36″ x 36″ Molded Sheets

Stockwell Elastomerics inventories 36″ x 36″ gum based silicone sheet in .188″ (3.18mm) through .500″ (12.7mm). Also in inventory is 50 durometer silicone in every standard gauge (.188″, .250″, .375″ and .500″) and 30, 40 and 70 durometer silicone in many gauges from .188″ through .500″.

Specification Grade (SG) Molded Silicone Sheet offered by Stockwell Elastomerics fills a need for thicker gauge 36″ x 36″ sheets in 2 thicknesses: 0.375″ and 0.500″. These are gum based, peroxide cured compounds made in 5 different durometers: 30, 40, 50, 60 and 70. SG-300 to SG-700 silicone sheets are compounded with iron-oxide pigment, molded flat and post cured for 4 hours at 450°F to improve service in high temperature applications such as heat sealing, annealing and other high temperature uses. Other suppliers previously made .375” and .500” thick sheets that were produced on a rotocure, and the resulting cured silicone had a noticeable curl. In contrast, SG-300 to SG-700 sheets are molded flat to best serve the intended use.